Carburetor throttle control



- June 17, 1941. 1. E; COFFEY CARBURETOR THROTTLE CONTROL Fiied July 25,1940 FIG.3.

INVENTOR :gEN E. COFFEY W. m, u'

ATTORNEY Patented June 17, 1941 Irven E. Cofley, Normandy, Mo., assignorto Carter Carburetor Corporation, St. Louis, Mo., a corporation ofDelaware Application July 25, 1940, Serial No. 347,416

8 Claims. (01. 137-139) This invention relates to mechanism foractuation of the throttle valve in carburetors ior internal combustionengines.

The use of a liquid link to operatively connect the usual carburetorthrottle v'alve and-control pedal .in an automobile substantiallysimplifies the control over the usual mechanical linkage.

However, it is desirable to'vary the rate at which the valve responds todifferent portions of the pedal movement and, particularly, to providefor a slower actuation of the valve when the vehicle the throttle is atrest in its substantially fully open position.

Fig. 1 shows a portion of'an automobileengine 5 having an intakemanifold 6 and a carburetor I mounted thereon. The carburetor has athrottle valve 8 which carries an arm 9 for actuation of the valve.Pivotally mounted on the floor board iii is a pedal ll connected to thecarburetor throttle by means of a liquid link mechanism, to

is accelerating from low speeds, than during the latter part of thethrottle opening movement when the car is in 'high gear. Also, it isirequently desirable to retard the latter portion of the closingmovement of the throttle so as to rapid rate. so faras I amaware,"neither of the above results has been obtained with the hydraulicor'liquid link throttle controls heretofore known. 1

Accordingly, it is an object of the present invention to provide meansfor varying the rate of actuation of the throttle valve, provided with ahydraulic control, relative to corresponding movement of the controlpedal according to the position of the valve. g A more detailed objectis to provide an hydraulic control for a carburetor throttle embodyingmeans to retard the first part of the opening movement of the throttlevalve, and the last part of the closing movement thereof, relative tothe corresponding movements of the throttle pedal. Certain features ofthe present invention are shown and claimed in a co-pendlng applicationfor reissue filed June 8, 1940, Serial No. 339,581, in the name of thepresent inventor.

prevent stalling of the engine and eliminate the i be describedhereafter, whereby depressing of the throttle pedal serves to open thevalve in the usual manner. Y

A cylinder i2 is secured to the engine block adjacent the carburetor bymeans of a bracket l2 and slidably receives a portion of plunger ll(Figs. 2, 3 and 4). A second cylinder l5 and a third cylinder [6 arerigidly mounted adjacent the iioor board by means of a bracket l'l.Cylinder l5 slidably receives a piston plunger 18 having a piston rod l9slidable through cylinder head 20. Movable in cylinder I6 is a loose ortree plunger 2lconstantly urged toward the left by a coiled spring 2la.Cylinders II and I6 are both secured to a base plate 22 projecting frombracket I1 and are connected by a cross passage 23 in the plate.

- Cylinders l2 and ii are connected by a tube 24 In the accompanyingdrawing which illustrates this invention: Fig. 1 is a diagrammaticrepresentation of a portion of an automobile engine and carburetorthrottle control constructed in accordance with the invention;

Fig. 2 is a sectional view showing the liquid link elements 0! thethrottle control with the valve in the closed throttle position.

Fig. 3 is a view similar to Fig. 2 but showing the parts in the positionassumed immediately after the throttle pedal has been depressed rapidly,and

Fig. 4 is a view similar to Figs. 2 and 3 but showing the parts in thepositions assumed when which also intersects passage 23. Piston I4 isconstantly urged to the right by a coiled spring. which also serves as athrottle closing spring whereby, when pedal II is released, the throttlevalve will be automatically returned to its closed position.

Piston II, which may be termed the driven member of the liquid link, hasa piston rod 2' which is connected by means of a link 21 to throttle arm8. Projecting in the opposite direction frompiston I4 is a steppedneedle 22 which, when the throttle valve is near its closed position, asin Fig. 2', enters a restriction 29 through which tube 24 communicateswith the interior of cylinder l2 so as to restrictthe passage of liquidto and from this cylinder.

The-mechanism operates as follows: Cylinder l8, plunger 2! and spring 2la iorm,i

effect, a resilient chamber structure in communithrottle openingmovement, greater back pressure will result in cylinder l5, tube 24, andpassage 23 at such time than when the throttle is further opened andneedle 28 has been withdrawn from restriction 29. A portion of theliquid discharged from cylinder l will enter cylinder l2, moving pistonl4 to the left against spring and opening the throttle valve. Obviously,when the throttle has opened far enough to withdraw needle 28 fromrestriction 29, continued actuation of pedal II, at the same speed asduring the first part of its movement, will produce less pressure intube 24 and, accordingly, more liquid will enter driven cylinder l2 andless will enter resilient chamber IS. The result of this is that afterneedle 28 is withdrawn from restriction 29, the throttle valve willrespond to depression of pedal II at a fasterrate than during the firstpart of the throttle opening movement. This is desirable since suchthrottle movement ordinarily occurs when the vehicle is beingaccelerated in a lower or more powerful gear ratio, when a slightopening movement of the throttle greatly increases the speed and poweroutput of the engine. When the throttle has been opened farther and thevehicle is in high gear, the engine does not respond as rapidly toopening movements of the throttle and the valve can be opened fasterwithout discomfort.

In Fig. 3, pedal II has been substantially fully depressed and piston l8moved to its extreme inward position at a rapid rate so as to build upsufficiently high pressure in cross passage 23 to substantially fullycompress spring 2la so that most of the liquid discharged from cylinderI5 enters the resilient chamber l6 and a relatively small part thereofenters driven cylinder I2 so as to displace piston I4 the relativelysmall amount shown. After piston l8 comes to rest, spring 2la, beingstronger than throttle return spring 25, forces liquid from cylinder l6into cylinder l2 and further opens the throttle. Thus, the rate at whichthe throttle valve can be opened is limited, a feature which isfrequently desirable in order that the valve opening movement berestricted to the rate at which the engine can respond. This feature isclaimed in the above-mentioned copending application Serial No. 339,581.

In Fig. 4, spring 2| has again expanded to force all the liquid fromcylinder l6 into driven cylinder l2 and to displace piston Hi to itsextreme left hand position, in which the throttle valve is fully opened.The throttle valve will be held in its extreme left hand position aslong as piston i8 is maintained in its fully open position. When pedalII is again released, piston l4 will be forced to the right under theinfluence of spring 25, ejecting liquid from cylinder I2 into drivingcylinder 15. As the throttle approaches its closed position, needle 28again enters restriction 29 so as to retard the rate of ejection ofliquid from cylinder l2 and consequently further closing movement of thethrottle valve.

All the above functions occur without noticeable variation in theresistance of pedal move ment and thus, automatically, soft andcomfortable acceleration through the lower gears is as sured by the slowinitial opening movement of the throttle valve without consciousvariation in the force applied to the throttle pedal by the driver.Moreover,the throttle cannot be opened at a faster rate than that towhich the engine can respond. Finally, the last part of the closingmovement of the throttle is retarded due to reentry of needle 28 intorestriction 29 at the end of tube 24.

The invention may be modified in various respects as will occur to thoseskilled in the art and the exclusive use of all such modifications ascome within the scope of the appended claims is contemplated.

I claim:

1. In combination with a carburetor throttle and manual controltherefor, a liquid link connecting said members for joint operationthereof, resilient means incorporated with said link for providingyielding response of said throttle to movement of said control, andmeans to retard the movement of said throttle between selected positionsthereof relative to corresponding movement of said control comprising anelement actuated with said throttle to restrict said liquid link whensaid throttle is between said positions.

2. In combination with a carburetor throttle member and a manual controlmember therefor, a liquid link connecting said members, a resilientchamber device communicating with said fluid link, and means operablewith one of said members during at least a portion of the movementthereof to vary the resistance of said link to fluid flow therethroughwhereby a varied response of said throttle member is obtained fromuniform movement of said control member.

3. In combination with a carburetor throttle member and a manual controlmember therefor, a liquid link connecting said members, a resilientdevice in connection with said link permitting movement of said controlmember at a different rate of speed than the consequent speed of saidthrottle member, and means operable by one of said members during atleast a portion of the normal movement thereof to vary the resistance ofsaid link to fluid flow therethrough.

4. In combination with a carburetor throttle member and a manual controlmember therefor, a liquid link connecting said members for opening saidthrottle member, yielding means for closing said throttle member, ayielding device in connection with said liquid link for providing lostmotion between said members during opening of said throttle member, andmeans actuated by said throttle member when near its closed position toincrease the effective resistance in said liquid link andthereby retardopening and closing movements of said throttle member when adjacent saidposition.

5. In combination with a carburetor throttle and a manual controltherefor, driving and driven expansible and contractible chamberdevices, respectively, connected to said control and said throttle, apassage connecting said devices, a resilient chamber connected to saidpassage, and means actuated by said driven chamber device to restrictthe portion of said passage between the same and said resilient chamberdevice when said throttle is near its closed position whereby an openingmovement of said control at such time produces a relatively slowerthrottle movement than corresponding movement of said control when saidthrottle is in other positions.

6. In combinaion with a carburetor throttle member and a manual controlmember therefor, a liquid link connecting said members including anexpansible and contractible chamber device connected to said throttlemember, spring means normally urging said throttle member in the closingdirection and tending to contract said chamber device, and an elementactuated by said chamber device for increasing the resistance to chamberdevice.

8. In combination with a carburetor throttle member and a manual controlmember theredevice having a movable wall connected to said control, afluid passage. connecting said chamber devices, an additional resilientchamber device communicating with said passage, and means operable withone of said movable walls to vary the eiiective cross sectional area ofsaid connecting passage during the movement of said last mentioned wallso as to vary the proportions of fluid entering two of said chamberdevices during for, a liquid link connecting said members including anexpansible and contractible chamber device connected to each of saidmembers and'a tube connecting said devices, spring means for closingsaidthrottle member, resilient chamber structure in connection 'with saidlink, the cham.

ber device connected to said throttle member hav" ing a movable wall,and a projection carried b; said movable wall and disposed, to entersaid tube when said throttle member is near'its closed position torestrict. the passage of liquid therepast and retard the movement ofsaid movable wall and throttle member relative to the correspondingmovement of said control member.

IRVEN' E. COFFEY.

uniform expansion or contraction of said third-

